1. Field
The present invention relates to an electronic device, and more particularly, to a semiconductor memory device and a method of driving the same.
2. Discussion of Related Art
Instead of Hard Disk Drives (HDD), which are slow, heavy, large, and create noise due to the rotation of a physical disk, the use of semiconductor memory devices has increased.
Semiconductor memory devices are made of semiconductors such as silicon (Si), germanium (Ge), gallium arsenide (GaAs), and indium phosphide (InP). Semiconductor memory devices are generally classified into volatile memory devices and nonvolatile memory devices.
Volatile memory devices are unable to store data without a constant source of power. Examples of volatile memory devices are Static random access memory (SRAM), Dynamic RAM (DRAM), and Synchronous DRAM (SDRAM). Nonvolatile memory devices are able to maintain stored data even without a constant source of power. Examples of nonvolatile memory devices include Read Only Memory (ROM), Programmable ROM (PROM), Electrically Programmable ROM (EPROM), Electrically Erasable and Programmable ROM (EEPROM), flash memory, Phase-change RAM (PRAM), Magnetoresistive RAM (MRAM), Resistive RAM (RRAM), and Ferroelectric RAM (FRAM). Flash memory is generally divided into the NOR type and the NAND type.
To decrease cost while increasing storage capacity, research on semiconductor memory devices that can store two or more bits in one memory cell is being conducted.
When two or more bits are programmed in each memory cell within one page, program preparation work is required. A data buffer needs to receive page data, and a control logic needs to control the page data to be stored in a page buffer.